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cintunsigned

Behavior of unsigned int in C

The size of an unsigned int in C is 0 to 65,535 or 0 to 4,294,967,295.

I tested with the following codes in C:

unsigned int number = 0;
number -= 300;
printf("%d\n", number);

OUTPUT: -300

I remember that if the value of unsigned int variable goes below 0, it should wrap around and I was expecting the output to be something like 4294966996. However the output printed from the console is -300.

I tested similar statements in C++, it does give me 4294966996.

My question is: Why is the output -300 despite the fact that it is an unsigned int?

PS: I've looked through several posts with similar title, but they are not addressing the same issue:

signed vs unsigned int in C

Unexpected results on difference of unsigned ints

Solution

  • Because printf("%d\n", number); will print a signed value, even if the parameter is unsigned. Use printf("%u\n", number); for an unsigned value to be correctly printed.